sidef/scripts/mutual_recursion.sf

#!/usr/bin/ruby

func F {};
func M {};

F = func(n) { n > 0 ? (n - M(F(n-1))) : 1 };
M = func(n) { n > 0 ? (n - F(M(n-1))) : 0 };

[F, M].each { |seq|
    (0..19).map {|i| seq.call(i)}.join(' ').say;
}